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Metrolink Tier 4 Locomotive Project Receives Environmental Certification

Thursday September 3, 2020

Los Angeles – This week, the California Air Resources Board (CARB) issued a Tier 4 Verification Certificate for Metrolink’s new, clean diesel locomotives after Emissions Verification testing was successfully completed. The testing and certification confirm that Metrolink’s locomotives continue to operate at the Environmental Protection Agency’s highest standards for diesel locomotives -- Tier 4 -- even after the units have been in service for an extended period of time. At the time of testing, the locomotive analyzed had logged more than 100,000 miles of service.

“Tier 4” is the most stringent designation from the US Environmental Protection Agency for engines to dramatically reduce emissions.

“As the first passenger railroad in the nation to invest in and successfully implement Tier 4 technology, we recognize this verification is critical in affirming our commitment to accelerating a zero-emissions future,” said Metrolink Board Chair Brian Humphrey. “The Tier 4 locomotives are a part of our continued dedication to benefit the community and the environment.” Every year, Metrolink reduces greenhouse gas emissions by an estimated 130,000 metric tons.

Metrolink has worked with its Member Agencies, the California State Transportation Agency (CalSTA) and regulatory partners including the South Coast Air Quality Management District (SCAQMD) for funding support of the 40 new Tier 4 locomotives. The certificate is a requirement to receive previously awarded grant funding from SCAQMD.

The total project cost of $280 million was largely funded from the SCAQMD through the Carl Moyer Memorial Air Quality Standards Attainment Program, which granted funding of $110 million. Additional funds were provided by state ($132 million), federal ($21 million) and local ($17 million) sources.

Metrolink currently has 37 of the planned 40 Tier 4 locomotives operating in its fleet, with the final three scheduled to be placed in service this fall.

Tier 4 locomotives reduce emissions between 65% and 85% compared to Tier 2 and Tier 0 locomotives, respectively, which previously were in Metrolink’s original fleet. The last of Metrolink’s 38 Tier 0 locomotives was removed from service earlier this year.

As part of the CARB Tier 4 Verification Certificate testing, sensors capable of detecting precise levels of nitrogen oxide (NOx), the primary factor to smog, and particulate matter, which leads to soot, were mounted over the locomotive’s exhaust stack to record emissions.



Metrolink is Southern California's commuter rail service enabling people to connect to their jobs and explore all that the region has to offer. Metrolink has nearly 12 million boardings annually from people who ditch their cars to avoid gridlock, removing an estimated 9.3 million vehicles from the roads and reducing greenhouse gas emissions by 130,000 metric tons. Metrolink is the largest commuter rail agency in California based on route miles and the third largest in the United States operating seven lines along a 538-mile network that travels across Los Angeles, Orange, Riverside, San Bernardino and Ventura counties.